3 research outputs found
Fast-activating reserve power sources: is lead dead indeed?
No full textThe purpose of this research is to improve the performance and reduce the activation time of reserve power sources based on lead-acid systems at lower temperatures, down to –50 °C. Physico-chemical factors affecting the activation speed of reserve power sources based on Pb–HClO4–PbO2 and Zn–HClO4–PbO2 systems are investigated using chronopotentiometry, scanning electron microscopy, and standard contact porosimetry. Two approaches to the improvement of the low-temperature performance of power sources are used. The first one is based on the substitution of lead as anodic material with zinc. This allows the increase in discharge voltage and simultaneous decrease in activation time, but brings about the instability of discharge characteristics and, finally, deteriorates the reliability of power sources. The second approach is based on the use of PbO2 cathode material with enhanced nanoporosity. The chronopotentiometric method in galvanostatic mode is applied to the quality estimation of cathodes. The criterion of applicability of cathodes for reserve power sources consists in the low discharge overvoltage (0.1–0.2 V). Efficient performance of reserve power sources possessing the stable discharge voltage (1.5–1.8 V per cell) and the unprecedentedly short activation time (under 30 ms) even at lower temperatures (down to –50 °C) is achieved. The results are verified by fabrication and testing of pilot batches of miniaturized reserve power sources having microcells’ volume of 0.02 ml. The second approach to the improvement of power sources is transferred into the industrial production
Unraveling the Impact of Hole Transport Materials on Photostability of Perovskite Films and p–i–n Solar Cells
No full textWe investigated the
impact of a series of hole transport layer
(HTL) materials such as Poly(3,4-ethylenedioxythiophene) polystyrene
sulfonate (PEDOT:PSS), NiOx, poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine
(PTAA), and polytriarylamine (PTA) on photostability of thin films
and solar cells based on MAPbI3, Cs0.15FA0.85PbI3, Cs0.1MA0.15FA0.75PbI3, Cs0.1MA0.15FA0.75Pb(Br0.15I0.85)3, and
Cs0.15FA0.85Pb(Br0.15I0.85)3 complex lead halides. Mixed halide perovskites showed
reduced photostability in comparison with similar iodide-only compositions.
In particular, we observed light-induced recrystallization of all
perovskite films except MAPbI3 with the strongest effects
revealed for Br-containing systems. Moreover, halide and β FAPbI3 phase segregations were also observed mostly in mixed-halide
systems. Interestingly, coating perovskite films with the PCBM layer
spectacularly suppressed light-induced growth of crystalline domains
as well as segregation of Br-rich and I-rich phases or β FAPbI3. We strongly believe that all three effects are promoted
by the light-induced formation of surface defects, which are healed
by adjacent PCBM coating. While comparing different hole-transport
materials, we found that NiOx and PEDOT:PSS
are the least suitable HTLs because of their interfacial (photo)chemical
interactions with perovskite absorbers. On the contrary, polyarylamine-type
HTLs PTA and PTAA form rather stable interfaces, which makes them
the best candidates for durable p–i–n perovskite solar
cells. Indeed, multilayered ITO/PTA(A)/MAPbI3/PCBM stacks
revealed no aging effects within 1000 h of continuous light soaking
and delivered stable and high power conversion efficiencies in solar
cells. The obtained results suggest that using polyarylamine-type
HTLs and simple single-phase perovskite compositions pave a way for
designing stable and efficient perovskite solar cells
Unraveling the Impact of Hole Transport Materials on Photostability of Perovskite Films and p–i–n Solar Cells
No full textWe investigated the
impact of a series of hole transport layer
(HTL) materials such as Poly(3,4-ethylenedioxythiophene) polystyrene
sulfonate (PEDOT:PSS), NiOx, poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine
(PTAA), and polytriarylamine (PTA) on photostability of thin films
and solar cells based on MAPbI3, Cs0.15FA0.85PbI3, Cs0.1MA0.15FA0.75PbI3, Cs0.1MA0.15FA0.75Pb(Br0.15I0.85)3, and
Cs0.15FA0.85Pb(Br0.15I0.85)3 complex lead halides. Mixed halide perovskites showed
reduced photostability in comparison with similar iodide-only compositions.
In particular, we observed light-induced recrystallization of all
perovskite films except MAPbI3 with the strongest effects
revealed for Br-containing systems. Moreover, halide and β FAPbI3 phase segregations were also observed mostly in mixed-halide
systems. Interestingly, coating perovskite films with the PCBM layer
spectacularly suppressed light-induced growth of crystalline domains
as well as segregation of Br-rich and I-rich phases or β FAPbI3. We strongly believe that all three effects are promoted
by the light-induced formation of surface defects, which are healed
by adjacent PCBM coating. While comparing different hole-transport
materials, we found that NiOx and PEDOT:PSS
are the least suitable HTLs because of their interfacial (photo)chemical
interactions with perovskite absorbers. On the contrary, polyarylamine-type
HTLs PTA and PTAA form rather stable interfaces, which makes them
the best candidates for durable p–i–n perovskite solar
cells. Indeed, multilayered ITO/PTA(A)/MAPbI3/PCBM stacks
revealed no aging effects within 1000 h of continuous light soaking
and delivered stable and high power conversion efficiencies in solar
cells. The obtained results suggest that using polyarylamine-type
HTLs and simple single-phase perovskite compositions pave a way for
designing stable and efficient perovskite solar cells
